Relative changes in genetic variability and correlations in an early-maturing maize population during recurrent...

Area of Science:

• Plant breeding and genetics
• Agronomy
• Crop science

Background:

• Recurrent selection is a breeding strategy to improve quantitative traits in crops.
• Striga hermonthica is a parasitic weed that significantly reduces maize grain yield in Africa.
• Evaluating genetic variance is crucial for the sustainability of breeding programs.

Purpose of the Study:

• To assess changes in genetic variance, heritability, and genetic correlations after four cycles of selection in maize.
• To predict future gains for grain yield and Striga resistance.
• To determine the viability of continuing the recurrent selection scheme.

Main Methods:

• Four cycles of S(1) family recurrent selection were applied to TZE-Y Pop STR C(0.) maize population.
• Fifty S(1) families from each cycle were evaluated under Striga-infested and Striga-free conditions in Nigeria.
• Genetic variances, heritability estimates, and genetic correlations were analyzed.

Main Results:

• Advanced selection cycles showed increased genetic variances for grain yield and Striga damage under infestation.
• Selected maize cycles significantly out-yielded the original cycle.
• Realized gains for grain yield were lower than predicted, but adequate genetic variability remains.

Conclusions:

• The recurrent selection scheme has generated substantial genetic gains for grain yield and Striga resistance.
• Residual genetic variance in cycle 4 supports continued selection for further improvement.
• Optimizing selection strategies may be needed to bridge the gap between predicted and realized gains.